MXPA00011934A - Process for preparing monodisperse adsorber resins and their use. - Google Patents

Abstract

The present invention relates to a process for preparing mono-disperse adsorber resin gels by polymerizing monomer droplets to give monodisperse polymers, followed by haloalkylating and crosslinking the resultant polymers, and also relates to the use of these resins.

Description

PROCEDURE FOR OBTAINING ADSORPENT RESINS UNDISPASSED AND YOUR EMPLOYMENT. Field of the invention. The object of the present application is a process for obtaining adsorbent resins, in the form of a gel, monodispersed, by polymerizing droplets of monomers to give monodispersed polymers, haloalkylation and subsequent crosslinking of the polymers, as well as their uses. Description of the prior art. Polymeric adsorbers are adsorbents with good adsorption and industrial application properties. In many cases they clearly surpass those based on carbon and inorganics. Such polymeric adsorbers find their application in the adsorption of gaseous, liquid organic substances or dissolved organic products. The adsorption of organic products has a special meaning in this case, and the main point must be sought first of all in the treatment of wastewater. The separating properties of the adsorbent resins can also be exploited in chromatographic separation processes. In general, the preparation of the polymer adsorbers is described, for example, in US Pat. No. 5,416,124 or DD-A 249,703 by reaction of the corresponding polymers with a haloalkylation reagent, such as, for example, monochlorodimethylether or, a '-dichloroxylene. In another step of the synthesis, the introduced halogenoalkyl groups are subsequently crosslinked by means of a Friedel-Crafts catalyst in an inert swelling agent with liberation of hydrogen halide with the polymer structure. After removal of the agent from Ref: 124723 swelling the adsorbent resins are washed. In DD-A 249 703 as well as in US-A 5 460 725 or US-A 5 416 124 adsorbers are obtained according to the forms described above, firstly by chloromethylation of the copolymer with monochlorodimethyl ether and then subsequent crosslinking. In the case of DD-A 249 703, copolymers with a divinylbenzene content of 3 to 8% by weight are used. The chlorine content after chloromethylation should be between 11.5 and 17.8% by weight, which corresponds approximately to a degree of substitution of 40 to 70%. The further crosslinking of the dry, solvent-free polymer (maximum 5% methanol), containing chloromethyl groups, is carried out by reaction in a swelling agent such as dichloromethane or tetrachloroethane, with a Friedel-Crafts catalyst such as FeCl3, SnCl4 or A1C13, at temperatures above 75 ° C. The macroporous polymers, which are used in US Pat. No. 5,416,124, are, for example, styrene / divinylbenzene copolymers, which are prepared by the addition of a porogen, such as, for example, hydrocarbons with 6 to 8 carbon atoms. In addition, ethyl vinylbenzene or a mixture of both can be used instead of styrene. Chloromethylation should provide a degree of substitution of about 60 to 70%. Also US-A 5 416 124 discloses that macroporous monodispersed adsorbers can be obtained and that they offer special advantages in chromatography. Other synthesis strategies for obtaining such adsorbents according to US-A 4 191 813 are based on the subsequent crosslinking of vinylbenzyl chloride copolymers in the presence of a swelling agent by means of Friedel-Crafts catalysts or in the subsequent crosslinking of the polymers, which contain alkylating agents, acylating agents and sulfur halides. However, the last generation method has the drawback that during the synthesis, partially accessible educts, such as vinylbenzyl chloride or polyfunctional alkylating agents, are to be removed from the polymer again when the conversion occurs. be incomplete The disadvantage of the preparation described in US-A 5 416 124 and US-A 5 460 725 is thatFor the preparation of the copolymer, a porogen is required, which has to be discharged from the production process or it has to be recycled if necessary. DETAILED DESCRIPTION OF THE INVENTION The task of the present invention was to develop a process of obtaining as simple as possible for the adsorbents described above with a large surface, with improved stability, with improved adsorption properties as well as with a reduced pressure loss when they are crossed by a stream of liquid or gaseous medium. In this case it would be an advantage if obtaining the adsorbent resin could be included in a production process for anion exchangers or that one of the usual intermediates obtained from obtaining the anion exchangers could be transformed into the adsorbers. The solution of the task and, therefore, the object of the present application, consists in a process for obtaining adsorber resins, in the form of a gel, monodispersed, characterized in that a) monomer droplets consisting of at least one monovinylaromatic compound and by at least one polyvinylaromatic compound and / or optionally an initiator or a combination of initiators, to give a cross-linked, monodispersed polymer, b) this crosslinked, monodispersed polymer is subjected to haloalkylation with agents of haloalkylation such as for example monochlorodimethyl ether and c) the polymer in haloalkylated beads is subjected to a crosslinking in the presence of Friedel-Crafts catalysts. According to step a) of the process, at least one monovinylaromatic compound and at least one polyvinylaromatic compound are used. However, it is also possible to use mixtures of two or more monovinylaromatic compounds and two or more polyvinylaromatic compounds. Surprisingly, the monodispersed, gel-shaped adsorbent resins prepared according to the present invention have a higher yield, a high spherical quality, a high osmotic stability as well as a higher useful capacity in the application, than the adsorbers known to the state. of the aforementioned technique. In addition, the adsorbers prepared according to the invention exhibit good adsorption and desorption kinetics. The base, vinylaromatic, cross-linked, monodispersed polymer according to step a) of the process can be prepared according to the methods known for the literature. By way of example, such processes are described in US Pat. No. 4,444,961, EP-A 0 046 535, US Pat. No. 4,419,245, WO-A 93/12167, the content of which is covered by the present application with respect to to stage a) of the procedure. Preferably, the cross-linked, monodispersed vinylaromatic base polymer is prepared according to the seed / feed method (seed-feed method) according to EP-A 0 046 535 or EP-A 0 051 210. As a copolymer, In the process step a), for example, a copolymer with a monovinylaromatic compound and a polyvinylaromatic compound can be used in the meaning of the present invention. As monovinylaromatic compounds for the purposes of the present invention, monoethylenically unsaturated compounds such as styrene, vinyltoluene, ethylstyrene, α-methylstyrene, chlorostyrene, chloromethylstyrene, alkyl acrylates or alkyl methacrylates will be preferred in process step a). Especially preferred monoethylenically unsaturated compounds, in the sense of the present invention, are styrene or mixtures formed by styrene with the aforementioned monomers. Preferred polyvinylaromatic compounds in the sense of the present invention are, for step a) of the process, multifunctional, ethylenically unsaturated compounds, such as, for example, divinylbenzene, divinyl toluene, trivinylbenzene, divinylnaphthalene, trivinilnaphthalene, 1,7-octadiene, 1,5-hexadiene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate or allyl methacrylate. The polyvinylaromatic compounds will generally be used in amounts of 1 to 20% by weight, particularly preferably 2 to 8% by weight, based on the monomer or its mixture with other monomers. The type of polyvinylaromatic compounds (crosslinking agents) will be chosen based on the subsequent use of the polymer in the form of spheres. In many cases divinylbenzene is suitable. For most applications, commercial grades of divinylbenzene are sufficient, which contain, in addition to the isomers of divinylbenzene, also ethylvinylbenzene. In a preferred embodiment of the present invention, microencapsulated droplets of the monomers are used in process step a). For the microencapsulation of the droplets of the monomers, the known materials for use as complex coacervates, especially polyesters, natural and synthetic polyamides, polyurethanes or polyureas, are suitable. The gelatins are suitable in a particularly good manner, for example as a natural polyamide. These are used especially in the form of coacervate and complex coacervate. Complex coacervates containing gelatin in the sense of the invention are, above all, combinations of gelatin with synthetic polyelectrolytes. Suitable synthetic polyelectrolytes are copolymers with incorporated units of, for example, maleic acid, acrylic acid, methacrylic acid, acrylamide and methacrylamide. Particularly preferably acrylic acid and acrylamide will be used. Capsules containing gelatin can be hardened with customary curing agents such as, for example, formaldehyde or glutaraldehyde. The encapsulation of monomer droplets with gelatins, gelatin-containing coacervates and with complex coacervates containing gelatin is described extensively in EP-A 0 046 535. Methods for encapsulation with synthetic polymers are known. For example, condensation at the boundary surface between the phases is perfectly adequate, in which a reactive component dissolved in the droplets of the monomers is reacted, for example an isocyanate or an acyl chloride with a second reactive component, dissolved in the aqueous phase, for example an amine. The droplets of monomers, optionally microencapsulated, contain, if appropriate, an initiator or mixtures of initiators for the initiation of the polymerization. Initiators suitable for the process according to the invention are, for example, peroxy compounds such as dibenzoyl peroxides, dilauroyl peroxide, bis (p-chlorobenzoylperoxide), dicyclohexyl peroxydicarbonate, tereperoctoate. -butyl, tere hexanoate. -butylperoxy-2-ethyl, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane or tert-amylperoxy-2-ethylhexane, as well as azo compounds such as 2,2'-azobis (isobutyronitrile) or , 2'-azobis (2-methyliso-butyronitrile). The initiators are generally used in amounts of 0.05 to 2.5% by weight, preferably 0.1 to 1.5% by weight, based on the mixture of the monomers. Microporous or macroporous gel expression has already been described extensively in the specialized literature. Preferred pearl polymers in the sense of the present invention, prepared by stage a) of the process, have a structure in the form of a gel and are prepared by processes described in DE-A 19 852 667. The conversion of the copolymers to give the adsorbers is carried out in step b) of the process by haloalkylation and subsequent subsequent cross-linking of the haloalkyl groups with aromatic nuclei of the polymer structure. For haloalkylation, they are usually used, suitable reagents, preferably chloromethylmethylether. These reagents, especially chlorometilmethylether, can be used in non-purified form, which can contain chloromethylmethylether as secondary components, for example methylal and methanol. Chloromethylethylether is used in excess and acts not only as a reactant but also as a solvent and as a swelling agent. The use of an additional solvent is therefore not necessary in general. The chloromethylation reaction is catalyzed by the addition of a Lewis acid.

Suitable catalysts in the sense of the invention are, for example, ferric chloride (III), zinc chloride, stannic chloride (IV) and aluminum chloride. The reaction temperature during the haloalkylation can be in the range from 40 to 80 ° C. When working without pressure, a temperature range of 50 to 60 ° C is particularly suitable. During the reaction, volatile components such as hydrochloric acid, methanol, methylal, formaldehyde and, in part, chloromethylmethylether can be removed by evaporation. In the case where the haloalkylation is carried out with chloromethylmethylether, a washing with methylal, methanol and finally with water can be carried out for the removal of the chloromethyl methyl ether residue, as well as for the purification of the chloromethylate. In step c) of the process, the haloalkylated copolymer is converted into an adsorber according to known processes, such as those described, for example, in DD-A 249 207. The conversion can be carried out, if appropriate, directly in the Haloalkylating agent, or the haloalkylated copolymer can be substantially freed from the excess haloalkylating agent as a step prior to use in step c) of the process.

For this purpose, the haloalkylated polymer is dried, optionally after step d) of the process, swollen in a swelling partner, such as, for example, halogenated hydrocarbons or dichloroethane, a catalyst is added.

Friedel-Crafts, such as, for example, FeCl 3 (dry or dissolved), H 2 SO 4 or SnCl 4 and reacted at elevated temperature, preferably at the boiling temperature of the stirring medium, which may be identical to the swelling agent. According to experience, the reaction can be carried out safely at temperatures between 50 ° C and 150 ° C. The adsorbers prepared according to the invention and used for the removal of polar and non-polar compounds, organic or inorganic, for example particles of paints or heavy metals, from aqueous or organic solutions or gases, especially from the chemical industry, from the electro-industry or the edible goods industry. The adsorbers prepared according to the invention are preferably used for the removal of polar compounds from aqueous or organic solutions, for the removal of polar compounds from process flows in the chemical industry, for the removal of paint particles. from aqueous or organic solutions. for the adsorption of organic components from aqueous solutions, from air or gases, for example for the adsorption of aldehydes, ketones, aromatic or aliphatic hydrocarbons or of aromatic or aliphatic chlorohydrocarbons, especially of the aldehyde, ketone or chlorobenzene form, for the removal of heavy metals, for example arsenic or selenium from aqueous solutions. In addition, the adsorbers according to the invention can be used for the purification and treatment of water in the chemical industry and in the electronics industry, as well as in the foodstuffs industry, especially for the manufacture of very pure water, very pure chemicals and starches or its hydrolysis products. Furthermore, the adsorbers according to the invention can be used for the purification of aqueous solutions in the industries for the elimination of waste or for the use of waste as well as for the purification of waste water flows from the chemical industry as well as for combustion plants. of garbage. Another use of the adsorbers according to the invention is represented by the purification of infiltration waters from waste landfills. In addition, the adsorbers according to the invention can be used for the production of drinking water or groundwater. The adsorbers according to the invention can also be used for air purification, for example in closed rooms or for the purification of gases. The diameters of the monodispersed adsorbers will be adapted according to the task to be solved and are determined by the adsorbent power on the one hand and by the loss of pressure on the other hand. Large spheres in the purification of gases and air have thus been particularly proved in this way. The adsorbers according to the invention have, compared to the organic components, differentiated adsorption and desorption properties and can be used successfully in chromatography systems for the enrichment and separation of organic and / or inorganic components. In these systems, small sizes of the spheres are generally advantageous. Example 1. a) Obtaining the polymer. a.1) Obtaining a seed polymer. 1,960 ml of deionized water are placed in a 4-liter glass reactor. 630 g of a microencapsulated mixture consisting of 1.0% by weight of divinylbenzene, 0.6% by weight of ethylstyrene (used in the form of a commercially available mixture of divinylbenzene and ethylstyrene with 63% by weight) are added. divinylbenzene), 0.5% by weight of tert-butylper-oxy-2-ethyl hexanoate and 97.9% by weight of styrene, the microcapsules being constituted by a complex coacervate, hardened with formaldehyde, constituted by gelatin and an acrylamide / acrylic acid copolymer. The average particle size is 231 μm. The mixture is combined with a solution consisting of 2.4 g of gelatin, 4 g of sodium hydrogen phosphate dodecahydrate and 100 mg of resorcinol in 80 ml of deionized water, stirred slowly and polymerized, under stirring, for 10 hours at 75 ° C. The polymerization is then terminated by increasing the temperature to 95 ° C. The load is washed through a 32 μm sieve and dried. 605 g of a microencapsulated polymer are obtained in the form of spheres with a smooth surface. The polymers have a transparent optical appearance; The average particle size is 220 μm. The seed polymer has a volume-swelling index of 4.7 and a soluble part of 0.45%. a.2) Obtaining a copolymer. 416.9 g of the seed polymer from (a) and an aqueous solution consisting of 1100 g of deionized water, 3.6 g of boric acid and 1 g of sodium hydroxide are charged to a 4 liter glass reactor. sodium and the stirring speed is adjusted to 220 rpm (revolutions per minute). A mixture of 713.4 g of styrene, 70 g of divinylbenzene (80.0% by weight) and 6.3 g of dibenzoyl peroxide (75% by weight, moistened) is added over the course of 30 minutes. with water) as a feed. The mixture is stirred for 60 minutes at room temperature, the gaseous chamber being flushed with nitrogen. Then a solution of 2.4 g of methylhydroxyethylcellulose in 120 g of deionized water is added. The charge is heated to 63 ° C and left for 11 hours at this temperature, then heated for 2 hours at 95 ° C. The charge is washed, after cooling, thoroughly with deionized water through a 40 μm sieve and then dried for 18 hours at 80 ° C in the drying cabinet. 1,150 g of a copolymer in the form of spheres with a particle size of 370 μm are obtained. b) Chloromethylation of the copolymer. A mixture of 1,600 g of monochlorodimethyl ether, 165 g of methylal and 5 g of ferric chloride (III) is added in a 3-liter sulfonation vessel, and then 300 g of the copolymer from a) is added. The mixture is allowed to stand for 30 minutes at room temperature and is heated for 3 hours at reflux temperature (55 to 59 ° C). It is then stirred for a further 1.75 hours under reflux. Approximately 275 g of hydrochloric acid and low-boiling organic products are expelled during the reaction time. The suspension of the dark brown reaction is then filtered off, the product obtained is intensively washed with a mixture of methylal and methanol, then with methanol, then with deionized water. 680 g of polymer are obtained in chloromethylated beads, moistened with water. Chlorine content: 18.8%. In this case about 8 to 10 g of oligomers per 1000 g of polymer with an excess of methanol were precipitated from the filtrate of the reaction mixture. In this case 100 ml of the wetted chloromethylate of the nutscha weighs 65.9 g. These contain 12.45 g of chlorine which corresponds to 0.351 mol. c) Obtaining an adsorber. 1.5 g = 197 ml of chloromethylate in VE water are introduced under vibration and the suspension is transferred to a washing column. The supernatant water is allowed to overflow. Then steam is added to the washing column by means of a laboratory steam generator with a speed of 600 ml of condensate per hour. In total about 2.5-3 times the volume of the bed in condensate is adsorbed. The chloromethylate moistened with water is transferred to a 4-necked flask with thermometer, dropping funnel and water separator, combined with 460 ml of dichloroethane (DCE), and the reaction suspension is stirred for 30 minutes at room temperature. It is then heated, until the total elimination of the water, in the reflux water separator. Approximately 22 ml of water are removed. After the discharge of the water, 44 g of a 40% by weight solution of FeCl 3 at the reflux temperature are metered in over a period of 2 hours. The water, dosed through the solution, is discharged into the water separator. It is then heated to reflux for approximately 15 hours (bath temperature 120 ° C). Approximately 27 g of HCl are released. It is cooled to room temperature and approximately 325 ml of DCE are separated through a sieve tube. The raw adsorber resin, moistened with DCE (355 ml) is transferred to a washing column, then steam is added to the washing column by means of a laboratory steam generator with a speed of 600 ml of condensate per hour . The total adsorb 3-3.5 times the volume of the bed in condensate. Approximately 1,000 ml of condensate are isolated, 162 g = 130 ml of DCE and 885 g = 890 ml of aqueous phase being able to be separated. After cooling to room temperature, the beads are washed, firstly with 1175 ml of VE water (approximately 5 times the bed volume), then with 180 ml of 2N NaOH (approximately 0.5 times the bed volume) and then with 1,175 ml of VE water (approximately 5 times the volume of the bed) and separated from the water through a nutscha. Water VE means completely desalinated water. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (12)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. - Process for obtaining adsorber resins, in the form of a gel, monodispersed, characterized in that a) droplets of monomers consisting of at least one monovinylaromatic compound and at least one polyvinylaromatic compound and / or optionally an initiator are reacted. or a combination of initiators, to give a crosslinked, monodispersed bead polymer, b) this monodispersed, crosslinked bead polymer is subjected to a haloalkylation with haloalkylating agents and c) the haloalkylated bead polymer is subjected to cross-linking in presence of Friedel-Crafts catalysts.

2. Method according to claim 1, characterized in that step a) is carried out according to a sowing-feeding method.

3. Process according to claims 1 and 2, characterized in that monovinylaromatic compounds of the series consisting of styrene, vinyl-luene, ethylstyrene, α-methylstyrene, chlorostyrene, chloromethylstyrene, alkyl acrylates or alkyl methacrylates are used.

4. Method according to claims 1 and 2, characterized in that polyvinylaromatic compounds of the series consisting of divinylbenzene, divinyl toluene, trivinylbenzene, divinylnaphthalene, trivinilnaphthalene, 1,7-octadiene, are used. 1,5-hexadiene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate or allyl meta-crilate.

5. Process according to claim 1, characterized in that the droplets of the monomers are microencapsulated.

6. - Process according to claim 1, characterized in that the excess haloalkylation agent is removed as a step prior to final cross-linking.

7. Adsorbent resins in the form of gel, monodispersed, characterized because they are prepared by means of a) reaction of droplets of monomers consisting of at least one monovinylaromatic compound and at least one polyvinylaromatic compound and / or optionally an initiator or a combination of initiators to give a crosslinked, monodispersed polymer, b) haloalkylation of this cross-linked, monodispersed, polymer polymer with haloalkylating agents; and c) final cross-linking of the polymer in haloalkylated beads in the presence of Friedel-Crafts catalysts.

8. Use of adsorber resins in gel form, monodispersed, according to claim 7, for the elimination of polar or apolar compounds, organic or inorganic, or heavy metals of aqueous or organic solutions or gases.

9. Use according to claim 8, characterized in that aqueous or organic solutions or gases are purified from the chemical industry, from the electro-industry, from the foodstuffs industry, from the industries for the elimination of waste or for the use of waste.

10. Use of monodispersed adsorber resins in gel form, according to claim 7, for the production of potable water or groundwater.

11. Use of monodispersed adsorber resins in gel form, according to claim 7, in chromatography separation processes.

12. Use according to claim 8, characterized in that aromatic or aliphatic hydrocarbons or chlorinated aromatic or aliphatic hydrocarbons are adsorbed from air or gases, aldehydes, ketones.